The national office of Kappa Sigma said in a statement Wednesday that it was investigating last Friday's party for possible conduct unbecoming a chapter. It told its chapter in Durham, N.C., to shut down all activities pending completion of the investigation and a decision on punishment.

The Kappa Sigma Fraternity is a diverse group of men, with members from all walks of life. We celebrate this diversity, as it is one of the things that makes our Order so strong. The actions taken in association with the event in question are inconsistent with our values. I personally condemn that type of behavior.

An estimated 250 to 300 people gathered on campus Wednesday to protest the party, which was promoted through fliers and email messages that included stereotyped Asian spellings like "herro" and "peopre" and cartoonish images of the late North Korean dictator Kim Jong-il. It was promoted on Twitter with the hashtag #RacistRager.

Katherine Zhang, a senior and co-president of Duke's Asian American Alliance, read a statement at the rally declaring, "When you wrote, 'Herro Duke,' you were not just mocking an accent. You were mocking an immigrant's struggle to make it in this nation."

The fraternity declined NBC News' request for comment, but at a campus forum Wednesday night, its president, Luke Keohane, said, "Our actions were inexcusable," according to a report in the campus paper, The Chronicle.

The party threw the Duke University campus into turmoil. Jonathan Carlson of NBC station WNCN reports.

"We're not here because we want to defend ourselves," he said. "We're here because we want to learn."

It's not the first time the Duke chapter has been in trouble. It returned to campus only last year after having been dissolved in 2002 amid a misconduct investigation.

While the national fraternity has already suspended the Duke chapter, the university itself is holding off on any action.

"At the moment, we're not aware of any overt violations," Larry Moneta, Duke's vice president for student affairs, told NBC News. "Acting boorish and foolish is not in and of itself a violation."